When I was a child we used to freeze ice cream in ice trays covered with aluminum foil, taking them out once in a while and giving them a stir to prevent crystals from forming.

This will help prevent kidney stones or crystals in the urine.

To prevent crystals forming in homemade grape jam or jelly, fresh grape juice should be chilled overnight to promote crystallisation.

The scientists found that adding extra corn syrup prevented crystals from forming at all, and the candy ended up more like taffy than fudge.

Urease inhibitors are used to dissolve kidney stones (including struvite stones), prevent crystals from forming new kidney stones, and treat urinary tract infections.

Drink several extra glasses of fluid each day to prevent crystals from forming in the urine.